/**
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import com.google.inject.Binder;
import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.spi.BindingTargetVisitor;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.HasDependencies;
import com.google.inject.spi.InjectionPoint;
import com.google.inject.spi.InstanceBinding;
import com.google.inject.util.Providers;

import java.util.Set;

final class InstanceBindingImpl<T> extends BindingImpl<T> implements InstanceBinding<T> {

    final T instance;
    final Provider<T> provider;
    final ImmutableSet<InjectionPoint> injectionPoints;

    public InstanceBindingImpl(InjectorImpl injector, Key<T> key, Object source, InternalFactory<? extends T> internalFactory, Set<InjectionPoint> injectionPoints, T instance) {
        super(injector, key, source, internalFactory, Scoping.EAGER_SINGLETON);
        this.injectionPoints = ImmutableSet.copyOf(injectionPoints);
        this.instance = instance;
        this.provider = Providers.of(instance);
    }

    public InstanceBindingImpl(Object source, Key<T> key, Scoping scoping, Set<InjectionPoint> injectionPoints, T instance) {
        super(source, key, scoping);
        this.injectionPoints = ImmutableSet.copyOf(injectionPoints);
        this.instance = instance;
        this.provider = Providers.of(instance);
    }

    @Override
    public Provider<T> getProvider() {
        return this.provider;
    }

    public <V> V acceptTargetVisitor(BindingTargetVisitor<? super T, V> visitor) {
        return visitor.visit(this);
    }

    public T getInstance() {
        return instance;
    }

    public Set<InjectionPoint> getInjectionPoints() {
        return injectionPoints;
    }

    public Set<Dependency<?>> getDependencies() {
        return instance instanceof HasDependencies ? ImmutableSet.copyOf(((HasDependencies) instance).getDependencies()) : Dependency.forInjectionPoints(injectionPoints);
    }

    public BindingImpl<T> withScoping(Scoping scoping) {
        return new InstanceBindingImpl<T>(getSource(), getKey(), scoping, injectionPoints, instance);
    }

    public BindingImpl<T> withKey(Key<T> key) {
        return new InstanceBindingImpl<T>(getSource(), key, getScoping(), injectionPoints, instance);
    }

    public void applyTo(Binder binder) {
        // instance bindings aren't scoped
        binder.withSource(getSource()).bind(getKey()).toInstance(instance);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(InstanceBinding.class).add("key", getKey()).add("source", getSource()).add("instance", instance).toString();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof InstanceBindingImpl) {
            InstanceBindingImpl<?> o = (InstanceBindingImpl<?>) obj;
            return getKey().equals(o.getKey()) && getScoping().equals(o.getScoping()) && Objects.equal(instance, o.instance);
        } else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(getKey(), getScoping());
    }
}
